text: /*
  
  Sample code showing how to read and write PLY polygon files.
  
  Greg Turk, March 1994
  
  */
  
  #include <stdio.h>
  #include <math.h>
  #include "ply.h"
  
  /* user's vertex and face definitions for a polygonal object */
  
  typedef struct Vertex {
    float x,y,z;             /* the usual 3-space position of a vertex */
  } Vertex;
  
  typedef struct Face {
    unsigned char intensity; /* this user attaches intensity to faces */
    unsigned char nverts;    /* number of vertex indices in list */
    int *verts;              /* vertex index list */
  } Face;
  
  /* polygon description of an object (a cube) */
  
  Vertex verts[] = {  /* vertices */
    { 0.0, 0.0, 0.0},
    { 1.0, 0.0, 0.0},
    { 1.0, 1.0, 0.0},
    { 0.0, 1.0, 0.0},
    { 0.0, 0.0, 1.0},
    { 1.0, 0.0, 1.0},
    { 1.0, 1.0, 1.0},
    { 0.0, 1.0, 1.0},
  };
  
  Face faces[] = {  /* faces */
    { '\001', 4, NULL },  /* intensity, vertex list count, vertex list (empty) */
    { '\004', 4, NULL },
    { '\010', 4, NULL },
    { '\020', 4, NULL },
    { '\144', 4, NULL },
    { '\377', 4, NULL },
  };
  
  /* list of vertices for each face */
  /* (notice that indices begin at zero) */
  
  typedef int Vertex_Indices[4];
  Vertex_Indices vert_ptrs[] = {
    { 0, 1, 2, 3 },
    { 7, 6, 5, 4 },
    { 0, 4, 5, 1 },
    { 1, 5, 6, 2 },
    { 2, 6, 7, 3 },
    { 3, 7, 4, 0 },
  };
  
  /* information needed to describe the user's data to the PLY routines */
  
  char *elem_names[] = { /* list of the kinds of elements in the user's object */
    "vertex", "face"
  };
  
  PlyProperty vert_props[] = { /* list of property information for a vertex */
    {"x", PLY_FLOAT, PLY_FLOAT, offsetof(Vertex,x), 0, 0, 0, 0},
    {"y", PLY_FLOAT, PLY_FLOAT, offsetof(Vertex,y), 0, 0, 0, 0},
    {"z", PLY_FLOAT, PLY_FLOAT, offsetof(Vertex,z), 0, 0, 0, 0},
  };
  
  PlyProperty face_props[] = { /* list of property information for a vertex */
    {"intensity", PLY_UCHAR, PLY_UCHAR, offsetof(Face,intensity), 0, 0, 0, 0},
    {"vertex_indices", PLY_INT, PLY_INT, offsetof(Face,verts),
     1, PLY_UCHAR, PLY_UCHAR, offsetof(Face,nverts)},
  };
  
  
  
  /******************************************************************************
  The main routine just creates and then reads a PLY file.
  ******************************************************************************/
  
  main()
  {
  
  #if 1
    /* write a PLY file */
    write_test();
  #endif
  
  #if 1
    /* read a PLY file */
    read_test();
  #endif
  
  }
  
  
  /******************************************************************************
  Write out a PLY file.
  ******************************************************************************/
  
  write_test()
  {
    int i,j;
    PlyFile *ply;
    int nelems;
    char **elist;
    int file_type;
    float version;
    int nverts = sizeof (verts) / sizeof (Vertex);
    int nfaces = sizeof (faces) / sizeof (Face);
  
    /* create the vertex index lists for the faces */
    for (i = 0; i < nfaces; i++)
      faces[i].verts = vert_ptrs[i];
  
    /* open either a binary or ascii PLY file for writing */
    /* (the file will be called "test.ply" because the routines */
    /*  enforce the .ply filename extension) */
  
  #if 1
    ply = ply_open_for_writing("test", 2, elem_names, PLY_ASCII, &version);
  #else
    ply = ply_open_for_writing("test", 2, elem_names, PLY_BINARY_BE, &version);
  #endif
  
    /* describe what properties go into the vertex and face elements */
  
    ply_element_count (ply, "vertex", nverts);
    ply_describe_property (ply, "vertex", &vert_props[0]);
    ply_describe_property (ply, "vertex", &vert_props[1]);
    ply_describe_property (ply, "vertex", &vert_props[2]);
  
    ply_element_count (ply, "face", nfaces);
    ply_describe_property (ply, "face", &face_props[0]);
    ply_describe_property (ply, "face", &face_props[1]);
  
    /* write a comment and an object information field */
    ply_put_comment (ply, "author: Greg Turk");
    ply_put_obj_info (ply, "random information");
  
    /* we have described exactly what we will put in the file, so */
    /* we are now done with the header info */
    ply_header_complete (ply);
  
    /* set up and write the vertex elements */
    ply_put_element_setup (ply, "vertex");
    for (i = 0; i < nverts; i++)
      ply_put_element (ply, (void *) &verts[i]);
  
    /* set up and write the face elements */
    ply_put_element_setup (ply, "face");
    for (i = 0; i < nfaces; i++)
      ply_put_element (ply, (void *) &faces[i]);
  
    /* close the PLY file */
    ply_close (ply);
  }
  
  
  /******************************************************************************
  Read in a PLY file.
  ******************************************************************************/
  
  read_test()
  {
    int i,j,k;
    PlyFile *ply;
    int nelems;
    char **elist;
    int file_type;
    float version;
    int nprops;
    int num_elems;
    PlyProperty **plist;
    Vertex **vlist;
    Face **flist;
    char *elem_name;
    int num_comments;
    char **comments;
    int num_obj_info;
    char **obj_info;
  
    /* open a PLY file for reading */
    ply = ply_open_for_reading("test", &nelems, &elist, &file_type, &version);
  
    /* print what we found out about the file */
    printf ("version %f\n", version);
    printf ("type %d\n", file_type);
  
    /* go through each kind of element that we learned is in the file */
    /* and read them */
  
    for (i = 0; i < nelems; i++) {
  
      /* get the description of the first element */
      elem_name = elist[i];
      plist = ply_get_element_description (ply, elem_name, &num_elems, &nprops);
  
      /* print the name of the element, for debugging */
      printf ("element %s %d\n", elem_name, num_elems);
  
      /* if we're on vertex elements, read them in */
      if (equal_strings ("vertex", elem_name)) {
  
        /* create a vertex list to hold all the vertices */
        vlist = (Vertex **) malloc (sizeof (Vertex *) * num_elems);
  
        /* set up for getting vertex elements */
  
        ply_get_property (ply, elem_name, &vert_props[0]);
        ply_get_property (ply, elem_name, &vert_props[1]);
        ply_get_property (ply, elem_name, &vert_props[2]);
  
        /* grab all the vertex elements */
        for (j = 0; j < num_elems; j++) {
  
          /* grab and element from the file */
          vlist[j] = (Vertex *) malloc (sizeof (Vertex));
          ply_get_element (ply, (void *) vlist[j]);
  
          /* print out vertex x,y,z for debugging */
          printf ("vertex: %g %g %g\n", vlist[j]->x, vlist[j]->y, vlist[j]->z);
        }
      }
  
      /* if we're on face elements, read them in */
      if (equal_strings ("face", elem_name)) {
  
        /* create a list to hold all the face elements */
        flist = (Face **) malloc (sizeof (Face *) * num_elems);
  
        /* set up for getting face elements */
  
        ply_get_property (ply, elem_name, &face_props[0]);
        ply_get_property (ply, elem_name, &face_props[1]);
  
        /* grab all the face elements */
        for (j = 0; j < num_elems; j++) {
  
          /* grab and element from the file */
          flist[j] = (Face *) malloc (sizeof (Face));
          ply_get_element (ply, (void *) flist[j]);
  
          /* print out face info, for debugging */
          printf ("face: %d, list = ", flist[j]->intensity);
          for (k = 0; k < flist[j]->nverts; k++)
            printf ("%d ", flist[j]->verts[k]);
          printf ("\n");
        }
      }
      
      /* print out the properties we got, for debugging */
      for (j = 0; j < nprops; j++)
        printf ("property %s\n", plist[j]->name);
    }
  
    /* grab and print out the comments in the file */
    comments = ply_get_comments (ply, &num_comments);
    for (i = 0; i < num_comments; i++)
      printf ("comment = '%s'\n", comments[i]);
  
    /* grab and print out the object information */
    obj_info = ply_get_obj_info (ply, &num_obj_info);
    for (i = 0; i < num_obj_info; i++)
      printf ("obj_info = '%s'\n", obj_info[i]);
  
    /* close the PLY file */
    ply_close (ply);
  }
  
  